文档介绍：华中科技大学
硕士学位论文
变电站接地网电位参数计算及其故障诊断
姓名:许澜
申请学位级别:硕士
专业:高电压与绝缘技术
指导教师:张丹丹
2011-01-08
摘要
变电站接地网的良好状态是电力系统安全可靠运行的重要保证,接地网的参
数计算及其故障诊断在接地网状态监测中具有十分重要的实际意义。本文通过理
论分析,建立了接地网电位参数的计算模型,对接地网周围的电位分布进行计算,
提出了以地表电位分布来诊断接地网故障的思路,并结合灰色关联模型,提出了
基于 T 型关联模型的接地网故障诊断思路。
本文通过分析接地网的地中电流与电位的分布规律,利用场路结合的思想,
建立接地网地表电位计算模型。采用叠加法代替积分法求解空间电位参数,为了
达到简化计算的目的,对接地网导体进行了微元段剖分和相关的等效处理。通过
与 CDEGS 软件进行算例对比,证明本文的程序能够较为准确地对接地网地表电
位进行计算。
本文从静电场理论出发,对接地网导体中的电流和电位分布等相关因素做了
分析,提出了以地表电位分布来判断接地网是否出现断裂故障的诊断思路。利用
本文编制的接地网参数计算程序,对若干完整和故障状态的接地网进行了分析计
算。另外,还对接地网故障辨识进行了模拟实验,试验中分别取完整和故障状态
下的接地网进行电位的测量。计算和实验结果表明,当接地网某处发生断裂以后,
该处对应的地表电位值相对于故障前将有所下降。由此验证了地表电位分布可以
作为判断故障的依据。
最后,通过分析调研,提出了基于 T 型关联模型的接地网故障诊断方法。
在建立模型的过程中,引入自定义的“边缘系数”这一参量,来减小电场的不均匀
性对于地表电位分布的影响。通过建立相关的 T 型关联模型,对两个故障接地
网进行了分析计算,结果表明,这种诊断方法具有较好的计算结果,是一种无需
知道接地网拓扑结构的接地网故障诊断方法。

关键词:接地网;地表电位;故障诊断;灰色关联理论
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ABSTRACT
The condition of the substation grounding grid is vital for the safety of the power
systems. During the condition monitoring of substation grounding grid, the parameter
calculation of grounding grid and its fault diagnosis are very important and practical.
In this paper, based on theoretical analysis, the model of the grounding grid is
established, which can calculate the potential of the grounding grid. A diagnosis
method which is based on analyzing the surface potential distribution is proposed.
Through research of grey incidence analysis theory, a new diagnosis method which is
based on T’s correlation degree is suggested.
Through analyzing the distribution of current and potential in the soil, a model is
established, which is based on EMF-circuit theory. Superposition method is used in
the model. At the same time, subdivision and equivalent are adopted to Simplify the
calculation. Comparing with CDEGS, the accuracy of the calculation program of this
paper is Proved.
Based on theory of electrostatic field, the current and potential distribut